A novel clinical technique is proposed for the measurement of the pressure distribution beneath the normal and abnormal foot during locomotion. It is anticipated that this technique will, for the first time, provide the orthopaedist or physiatrist with both a quantitative measurement and a graphic representation of the temporal and spatial variations of the streses generated on the planter surface of the foot. Preliminary work with a related technique, impractical for clinical applications, has demonstrated the feasibility and potential of the proposed approach. The first phase of the proposed study (Year 1) involves development of a measurement system consisting of flexible piezoelectric transducer arrays of varying geometries and a common supporting data acquisition and graphic display package. In the second phase (year 2), a study will be made of the within and between subject variabilities of the pressure distributions generated by a population of "normal" subjects (n greater than or equal to 100) walking and running over a range of speeds. Techniques will also be developed for presenting these data in a form that shows both the mean stresses and their variations as functions of time and position. Finally, in Phase 3, the device will be applied to the study of several well defined groups of patients exhibiting a variety of lower extremity pathologies. These patients will be obtained through the Hershey Medical Center of The Pennsylvania State University. The aims of this phase will be: 1) to determine the pressure distributions characteristic of each pathology and the way in which these deviate from the norms established in Phase 2; 2) to investigate computer aided diagnosis of these pathologies using pattern recognition techniques; 3) to explore the use of the technique in the prescription and evaluation of orthotic devices; and 4) to provide a reference data base for use of the technique in clinical practice.